The joys of outsourcing 12 volt batteries

Elon was just discussing at the end of the conference call the 12 volt battery issue. They had purchased from an American reputable firm the Tesla S 12 volt lead acid batteries. That company outsourced to China. The Chinese company then turned around and outsourced to Vietnam.

Quality was poor and explains the 12 volt issues owners report.

Yup. That one kind of blew me away. Like I said in another thread, I hope that supplier feels like an idiot. I hope they lost the contract too!

So I have a Vietnamese battery??????? Yuck

Until it dies and you get it replaced! Haha!

Have they changed what they put in current builds?

Yes, Elon said they have a reliable source now.

I don't know if it's from a new supplier or not though. I missed that detail.

Nothing wrong with a Vietnamese battery, but the issue here is losing control of your supply chain. Tesla paid a price to a company that skimmed off a portion to deliver a battery. Then that company passed it to the Chinese who skimmed off another portion. Then passed it to a Vietnamese battery company that skimmed off another percentage to build the battery. Tesla did not get the expected quality and the cost of servicing these issues are passed on to Tesla and the customers. Meanwhile three companies got a cut of profits.

Having observed this for 20 years, I've seen PMs that have assumed you can outsource, offshore, onshore, or vendor out critical functions. I recall one saying "We can give this to the vendor and we don't have to worry about it." Wrong. You need to build in vendor management into the financial model.

Hopefully Tesla does a better job of writing contracts specifiying sub contracting in the future, or attempts to do a claw back on the 12 V battery manufacturer.

Kind of funny right now considering Elon was trying to give Boeing help with their battery issue a few weeks ago.

Regardless, seems like Tesla has been transparent on the battery issue, and resolving as they arise. Better if we had not had these though.

My livelihood being with semiconductor design & manufacturing, in particular when fabrication, assembly, test & materials are outsourced, you can't just shake the supplier's hand with the understanding that they will meet all requirements set forth in your procurement spec. You have to work quite extensively with the supplier & be on site for initial design and the validation process. Travel onsite to where the product is being manufactured to perform source inspection, verify compliance to specifications and success to extensive quality & reliabilty testing.

Maybe the Roadster, which was suppose to validate its long term reliabiity & quality did not have the same supplier for the 12V battery or the design of the battery was changed & not fully field tested.

I STILL think relying on a 12V lead acid battery (which die ALL THE TIME) to start the car and in the Tesla, is a pain in the ass to "jump start" since they don't give you terminals, is a BAD DESIGN DECISION. It is said it is needed as "backup" to power the car's computers in case the main battery gets drained. Well, it isn't a backup if it is REQUIRED to start the car. It is, in fact, a CRITICAL COMPONENT, with ZERO backups behind it.

The car could be designed to either not have a 12V battery, or the have a fail safe DC-DC converter that could be used for when the 12V battery dies, or as a last ditch, give us jump start terminals, so any ICE with cables could start our car.

Will Tesla make such a design fix???

Since the 12V battery is not subject to high heat from an ICE, is should last a long time. Does anyone know where the battery is located? It would be easy to put a load tester on it once a year and make sure the battery is healthy if we can get to it.

@Shop - so you can't use the terminals behind the nose cone to provide 12V to start the car?

That's all wrong. The 12V directly powers various small devices, like the doors and screens. And there are terminals accessible behind the nose cone.

Hmm, could save some weight by making a LiIon pack that fits where the 12V Dinosaur battery goes... Years later you could use either/or...

Redundancy is super in important in spaceflight, Elon above all should know better!

@rdalcanto - Like during the annual inspection that's now optional? ;-)

@brian, what's "all wrong"? If the 12v battery dies, can you start the car? Can you access the 12v terminals without tools? Where is it documented to access the 12v terminals?

Thinking about this from the perspective of a thief, if the 12 V is dead, you can't open the car doors, therefore cannot open the frunk. Likewise with the mobile app. And the 12V, I thought was under the frunk liner (could be wrong on this). The trunk is as tight as a gnats ass, so that's a no go. The only place I can think of is the charging port, which you can open from the outside of the car (secret ninja karate chop maneuver). Or put 12 terminals somewhere near the 12v battery.

Me, personally? Would not have put them behind the nose cone, as it's first at the scene of the accident, but perhaps they are well shielded.

@shop @jbunn

The 12 v terminal is behind the nose cone, which can be removed with a panel removal tool.

Brian H misses an important point - One of the big reasons for the 12V is to operate the contactors that isolate the battery pack. The contactors fail safe in the open position. 12V power is required to close the contactors and connect the battery to the motor.

@Shop - you are right; you would need some kind of tool to remove the nose - but any blade should do (though plastic would be required to reduce the risk of marking the nose)

Yes, I know about the nose cone. Removing the nose cone panel is not easy, not documented, and not recommended by Tesla. When I said Tesla could provide access to the 12V terminals, I meant in an easy way like you can on an ICE vehicle. When the 12V battery dies (and it will, given enough time, right???), Tesla's way of dealing with it is to send a tech or a flatbed truck, so even they don't want you to start taking apart your car.

My point is that the 12V battery system is not well designed. It is a single point of failure with no backup.

Driving accessories with dedicated stepdown transformer voltages requires a far more complex setup. Keeping a 12V topped up is (in theory) much easier. But it requires a non-crap 12V.

A 12V lithium battery is a nice idea, but it can't really thermally manage -itself-, so starting in cold temperatures could be a problem. A 40ah lithium battery would also be reasonably expensive to replace when it fails...

@Brian - you don't use step down transformers in a DC powered car. You use a DC-DC converter which is a somewhat complex assembly of discrete electronics. But DC-DC converters are reliable. 12V lead acid batteries are not. I don't know, maybe Tesla has figured out how to reliably get 8 years from a lead acid battery (well, obviously not yet since a bad batch doesn't even last 6 months!), but I really, really doubt it.

therealmach3, that story is exactly what I thought of when I ready about this 12-volt battery outsourcing shenanigans.


Thanks for the excellent explanation of the 12v battery. That makes perfect sense. The contactors have to have power to connect the main pack, and some things have to still work when the main pack is not connected.

Anybody else consider that since China is building an electric car sponsored by the Chinese government that they gave an undercutting bid to the supplier and then deliberately contract with the Vietnam company for less than specified quality to undermine Tesla's position in the market ?

Just a thought !


@shop - Not sure ICE are any better. Almost every luxury car (and not so luxury cars) uses a FOB to get into the car. If the battery is dead, you don't get in. Usually this means you can't release the hood. And if you do get the hood open, surprise - the battery is either hidden under big plastic engine covers that requires tools to get to, or it's under the back seat.

My experience with ICE lead-acid batteries is when they get to the end of life they give you a bit of warning (1-2 days) with cranking slowness. No dashboard warning usually appears with battery death.

The Tesla 12v battery is also monitored and has a warning when it's about to die. Not sure how much warning you get, and it seem some batteries have died too quickly to get a proper warning.

@shop - it is super-easy to remove the nose cone and access the 12v terminals. No tool required. although some recommend a panel remover tool, that's a waste of money. I have had mine off four times so far (testing locations for our EZ-Pass transponder). All you need is a credit card or similar thin piece of plastic under the lower edge to get enough purchase to pull it off with your fingers. Pops right off and snaps back on in seconds.

@Pungoteague_Dave - from a similar thread over at TMC: "Spent an hour on the phone with Tesla trying to remove it [nose cone]. Actually, they were not giving me the right procedure as my nose cone was a different design that they've expected."

@TeslaTap - ICEs ARE better in this respect. Many people have had their Tesla 12V battery die with NO warning. The jump terminals are NOT easily accessible.

It would have been relatively easy for Tesla to incorporate a self-jump mechanism with a dedicated DC-DC converter. A protected, but accessible switch that is effectively a manually operated main pack contactor switch. That is only one way to solve this. Actually providing easy access to the jump terminals is another.

This is a design flaw - obviously Tesla never thought through what happens when the 12V battery dies. I hope they are paying attention and don't think that simply getting more reliable 12V batteries 'solves' the problem. That's a band-aid, not a solution.

@shop: The person on TMC does not know what they are talking about and your comment is a misdirection based on old news. Please take it from someone who has done it. The first time it took me five minutes start to finish. Now it is seconds. I agree that getting the nose off to access the terminals isn't obvious, but once done, it is as easy as opening your toothpaste, with even less complex wrist motions. It isn't necessary to complain about nonissues?

How do you know they didn't know what they were talking about? Have you talked to him? The post I quoted was posted today. How is that old news?

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